# US 2017/0283891 A1 · Method for detecting air flow distribution in blast furnace

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- Number: US 2017/0283891 A1
- Document ID: US20170283891A1
- Status: Published application
- Kind: A1
- Application number: 15/507,961
- Filed: 2014-09-19
- Published: 2017-10-05
- Earliest claimed: 2014-09-03
- Assignees: Institute of Research of Iron and Steel, Jiangsu Province/Sha-Steel, Co., Ltd.
- Applicants: Institute of Research of Iron and Steel, Jiangsu Province/Sha-Steel, Co. Ltd.
- Inventors: Huatao ZHAO; Ping DU
- Web page: https://patentgrep.com/patent/US20170283891A1

## CPC

- C21B 7/24: Test rods or other checking devices
- C21B 5/00: Making pig-iron in the blast furnace
- C21B 5/006: {Automatically controlling the process}
- C21B 5/008: {Composition or distribution of the charge}
- C21B 7/103: {Detection of leakages of the cooling liquid}
- C21B: MANUFACTURE OF IRON OR STEEL (preliminary treatment of ferrous ores or scrap C22B1/00)

## Abstract

A method for detecting an air flow distribution in a blast furnace, taking into account a heat exchange between an air flow and a solid material bed and the effect of a distribution of a material layer structure in a radial direction of a blast furnace on the radial air permeability of blast furnace, which affects a mode of air flow distribution, wherein the distribution of the air flow and the radial material layer structure of the blast furnace can be calculated by combining a cross-shaped temperature-measuring gun and other main blast furnace operating parameters. According to the detection method, a blast furnace operator can timely and accurately infer, from a change in a current radial air flow temperature distribution, the direction of change of the distribution of the air flow and the radial material layer structure at a furnace throat portion.

## Claims

### Claim 1

A method for detecting gas flow distribution in blast furnace, wherein the method comprises the following steps:
a) dividing a cross-section of blast furnace throat according to the number and positions of temperature-measuring devices at the top of blast furnace to obtain N temperature-measuring device regions; wherein the N is a natural number greater than or equal to 1;
b) obtaining a solid-gas heat flow ratio of each of the temperature-measuring device regions according to temperature values from each of the temperature-measuring devices and a balance equation between a heat flow rate of gas and a heat flow rate of solid in a lump zone of blast furnace below corresponding temperature-measuring device region;
c) establishing a function relation between a thickness ratio of burden material layers and a gas flow rate within each of the temperature-measuring device regions according to the solid-gas heat flow ratio of each of the temperature-measuring device regions;
d) obtaining the thickness ratio of burden material layers within each of the temperature-measuring device regions according to pressure drop per unit length of burden layer, particle size distribution of the burden materials and gas resistance equation of each lump zone of blast furnace, and obtaining the gas flow rate of each of the temperature-measuring device regions according to the thickness ratio of burden material layers within each of the temperature-measuring device region above and the function relation between the thickness ratio of burden material layers and the gas flow rate within each of the temperature-measuring device region obtained in the above step c); and
e) plotting the region distribution of each of the temperature-measuring device regions and the gas flow rate thereof, to obtain a detection result of the gas distribution.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the method further comprises, after step d):
d#) obtaining by calculation an average thickness ratio of burden material layers according to the thickness ratio of burden material layers within each of the temperature-measuring device regions, and obtaining a total volume of gas flow passing through the temperature-measuring device regions according to gas flow rate in each of the temperature-measuring device regions, to further obtain a total heat of gas flow passing through the temperature-measuring device regions;
comparing the average thickness ratio of burden material layers obtained in the above step with a theoretical average thickness ratio of burden material layers, to obtain an error σ1; comparing the total volume of gas flow passing through the temperature-measuring device regions obtained in the above step with a theoretical total volume of furnace top gas flow, to obtain an error σ2; and comparing the total heat of gas flow passing through the temperature-measuring device regions with a theoretical total heat of furnace top gas flow, to obtain an error σ3;
modifying the pressure drop per unit length of burden layer and the particle size distribution of burden materials if one or more of the errors σ1, σ2, and σ3 has a value greater than or equal to 5%, and performing the step d) again, until the value of each of the errors σ1, σ2, and σ3 is less than 5%; and
performing the above step e) if the value of each of the errors σ1, σ2, and σ3 is less than 5%.

### Claim 3 (depends on 2)

The method according to claim 2, wherein the burden materials are ore and coke, and the theoretical average thickness ratio of burden material layers is calculated based on the formula: X0=[LO/(LO+LC)]0, wherein Lo is a thickness of ore layer, and Lc is a thickness of coke layer.

### Claim 4 (depends on 2)

The method according to claim 2, wherein the thickness ratio of burden material layers within each of the temperature-measuring device regions is xi, the average thickness ratio of burden material layers is Xt, and the average thickness ratio of burden material layers is calculated based on the formula:
X
t
=
∑
i
=
1
N

x
i
·
S
i

/

A
wherein Si is an area of each of the temperature-measuring device regions, and A is a total area of the cross-section of the blast furnace throat.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the burden materials are ore and coke, the thickness ratio of burden material layers in the temperature-measuring device region is xi, the gas flow rate in the temperature-measuring device region is ui, then the function relation between the thickness ratio of burden material layers and the gas flow rate in the temperature-measuring device region is:
x
i
=
(
C
s

G
s
C
g

G
g
)
i
·
(
C
g
)
i

(
ρ
g
)
i
C
s

(
ρ
O
-
ρ
C
)

v
i

u
i
-
ρ
C
(
ρ
O
-
ρ
C
)
wherein Cg is a specific heat of gas, Cs is a specific heat of solid, Gg is a flow rate of gas, Gs is a flow rate of solid, ρ is a density of furnace top gas, v is a descent velocity of a solid burden bed, ρO is a density of ore, and ρC is a density of coke.

### Claim 6 (depends on 1)

The method according to claim 1, wherein the gas resistance equation of each lump zone of blast furnace is:
(
Δ


P
L
)
i
=
[
k
1
⋆

(
1
-
ɛ
)
2
D
p
2

ɛ
3
·
μ


u
+
k
2
⋆

(
1
-
ɛ
)
D
p

ɛ
3

ρ


u
2
]
i
wherein, k1* is a viscous resistance coefficient, k2* is an inertia resistance coefficient, ΔP/L is a pressure drop per unit length, ε is a burden bed porosity, Dp is an average particle diameter of particles, μ is a gas viscosity, u is a gas flow rate, and ρ is a gas density;
the viscous resistance coefficient and the inertia resistance coefficient of the coke are respectively:
k1*=450·(Dp·10)0.84,k2*=2.2·(Dp·10)0.04;
the viscous resistance coefficient and the inertia resistance coefficient of the ore are respectively:
k1*=260·(Dp·10)0.84,k2*=1.2·(Dp·10)0.04.

### Claim 7 (depends on 1)

The method according to claim 1, wherein the pressure drop per unit length of burden layer in each lump zone of blast furnace is equal,
the pressure drop per unit length of burden layer in each lump zone of blast furnace is equal to the sum of a pressure drop per unit length of coke layer and a pressure drop per unit length of ore layer in said lump zone of blast furnace.

### Claim 8 (depends on 1)

The method according to claim 1, wherein the temperature-measuring device is a cross-shaped temperature-measuring gun.

### Claim 9

A system for detecting gas flow distribution in blast furnace, wherein the system comprises:
a division unit, configured to divide a cross-section of blast furnace throat according to the number and positions of temperature-measuring devices at the top of blast furnace to obtain N temperature-measuring device regions; wherein the N is a natural number greater than or equal to 1;
a first attainment unit, configured to obtain a solid-gas heat flow ratio of each of the temperature-measuring device regions according to temperature values from each of the temperature-measuring devices and a balance equation between a heat flow rate of gas and a heat flow rate of solid in a lump zone of blast furnace below corresponding temperature-measuring device region;
an establishment unit, configured to establish a function relation between a thickness ratio of burden material layers and a gas flow rate within each of the temperature-measuring device regions according to the solid-gas heat flow ratio of each of the temperature-measuring device regions;
a second attainment unit, configured to obtain the thickness ratio of burden material layers within each of the temperature-measuring device regions according to pressure drop per unit length of burden layer, particle size distribution of the burden materials and gas resistance equation of each lump zone of blast furnace, and to obtain the gas flow rate of each of the temperature-measuring device regions according to the thickness ratio of burden material layers within each of the temperature-measuring device region above and the function relation between the thickness ratio of burden material layers and the gas flow rate within each of the temperature-measuring device region obtained in the above step c); and
a result unit, configured to plot the above distribution of each of the temperature-measuring device regions and the gas flow rate thereof, to obtain a detection result of the gas distribution.

### Claim 10 (depends on 9)

The detection system according to claim 9, wherein the system further comprises:
a verification unit, configured to obtain by calculation an average thickness ratio of burden material layers according to the thickness ratio of burden material layers within each of the temperature-measuring device regions, and to obtain a total volume of gas flow passing through the temperature-measuring device regions according to gas flow rate in each of the temperature-measuring device regions, to further obtain a total heat of gas flow passing through the temperature-measuring device regions;
wherein the average thickness ratio of burden material layers obtained in the above step is compared with a theoretical average thickness ratio of burden material layers, to obtain an error σ1; the total volume of gas flow passing through the temperature-measuring device regions obtained in the above step is compared with a theoretical total volume of furnace top gas flow, to obtain an error σ2; and the total heat of gas flow passing through the temperature-measuring device regions is compared with a theoretical total heat of furnace top gas flow, to obtain an error σ3;
the pressure drop per unit length of burden layer and the particle size distribution of burden materials are modified if one or more of the errors σ1, σ2, and σ3 has a value greater than or equal to 5%, and the step d) is performed again, until the value of each of the errors σ1, σ2, and σ3 is less than 5%; and
the step e) is performed in the case that the value of each of the errors σ1, σ2, and σ3 is less than 5%.